Alexander mitscherlich



Mrs STATES ATENT 7 FFEQEQ ALEXANDER MITSCHERLIGH, OF FREIBURG, BADEN, GERMANY.

SIZING PAPER.

SPECIFICATION forming part of Letters Patent No. 336.013, dated February 9, 1886.

To all whom it may concern:

sized.

Be it known that I, ALEXANDER llIITSOHER- LIOH, of Freiburg, Grand Duchy of Baden, Germany, and a subject of the Emperor of Germany, have invented certain Improvements in Sizing Paper, of which the following is a specification.

My invention consists in a new method for the sizing of paper materials, wherein substances having a tanning action and which precipitate animal glue are employed, as fully described hereinafter.

The principal methods now in use for sizing paper are those in which glue and resin sizing are employed. In the first of these methods the ready-made paper receives a coating of sizing, whereas the internal parts remain un- In the second method the separate fibers of paper are surrounded on their upper surface by the sizing material, and are stuck together by it.

According to the present invention the sizing of paper materials is effected by precipitating glue or resin soap by means of fluids containing tanning materials that precipitate glue, and this method offers very material advantages ovcr other systems of sizing paper, particularly on account of the fact that thereby a paper easily soluble in wateris obtained.

The methods hereinafter described are based on the property of the solutions of the tanning materials (in dilute condition) of pro ducing,with asolution of resin soap or of glue, precipitates of a strongly glutinous nature, which, provided the precipitation in the pulp is carried out in a proper manner, envelops the surfaces of the fibers in such a way that the latter are mainly cemented together from the outside. According as resin soap or glue has to be precipitated by the tanning-material solution the practical carrying out of this method will have to be modified both as re gards the proportions of the quantities and also in some other points, and consequently they must be described separately.

In order to carry out the sizing with tanningmaterial solution and resin soap there is poured over the pulp, ready prepared in the rag-engine for sizing, for every one hundred kilograms thereof about twelve liters of fluid containing tanning material resulting from Application filed October 2, 1884. Serial No.144,559.

(No specimens.)

sulphite boiling, and correspondingin its efsuited for this purpose twenty per cent. of 1 resin soap, is then poured in gradually and in the proportion of about twenty-four liters to about one hundred kilograms of pulp, taking care to stir the latter up continually. By this means the resin soap solution comes into close contact with the fluid containing tanning n1aterial, and a strongly glutinous precipitate forms on the fibers, which is accelerated and completed if, after pouring in the solution of resin soap, the pulp is properly stirred up for a time. It is advantageous to have in this case an excess of the tanning-material fluid, its existence being indicated in the acid reaction of the mass. These operations can be carried out in the reversed order. The proportions of quantities can of course be altered according to the degree ofsizing required. laper sized in this way distinguishes itself in many respects from other sorts of paper prepared according to the common methods of sizing, and in some paper materials results of a very peculiar nature have been obtained. Thus, for instance, in the case of sulphite celulose, when sized according to the above method and under similarproportions, a comparatively very firm and not too brittle ma terial is obtained which is easily soluble again in a large quantity of water. Sizing by precipitation of glue by means of fluids containing tanning material is also carried out in the pulp and in most advantageous manner, as will be explained hereinafter, for two entirelydifferent kinds of fiber materials. An acid reaction, perceptible by the aid of litmus paper, is produced in the pulp by adding an acid to itfor instance, muriatic acid, in the ease of sulphite cellulosewhercupon about 1.7 kilograms of glue dissolved in as little fluid as possible containing about sixteen liters of tanning material are mixed with every one hundred kilograms ofpulp. The tanningmaterial fluid results from sulphite boiling and corresponds in its efiect on the glue solution with 6.5 per cent. of tanning solution.

The mixing is carried out in the following manner: A jet of the tanning-material solution is fed in continuously from one side of the ragengine containing the pulp, while the glue solution is injected from the other side. Care must be taken that the solutions get as much mixed as possible with the pulp by means of the action of the rag-engine, the mass being then rapidly diluted to a considerable extent. By the contact of the two diluted solutions the two bodies are precipitated continuously out of the fluid. The precipitation thus effected envelops the surface of the smallest particles of pulp with a glutinous substance. The influx of the solutions must not be too rapid. as otherwise the precipitations will not descend in fine subdivision, but in coarse masses, upon the fibers, and will cause detrimental spots in the paper. As soon as the necessary quantities of glutinous substances have been imparted to the pulp, tanning-n'laterial solution may advantageously be added, this being thoroughly mixed up with the pulp, and the mass then lelt alone for a quarter of an hour.

It has been found that in sizing wood paste by itself as a paper material the most practical proportions when this process is used are about four kilograms ofsizing and about thirtysix liters of the above fluid tanning material to every one hundred kilograms of stuff.

The relative proportions of paper materials and glutinous substances, as also the operation and the kind of tanning material, can be altered according to the qualities the product is required to have.

Too great an addition of the sizing materials may cause the paper to adhere to the machine, which evil can, however, generally easily be remedied by adding some such substance as starch-paste, for instance.

tested, and it was found that it'was able to bear even eleven kilograms, whereas common printing -paper of the same breadth and of about similar weight could not bear more than from two to six kilograms.

Papers sized according to the method above described have also the peculiar characteristic that their sizing can be quickly removed by means of plenty of water, whereby the paper is converted in a short time and without in juring the fibers? very materially into serviceable pulp, which can be immediately used again.

In the case of paper which is strongly sized with tanning material and glue, it is advisable, in order to make it dissolve easily in water, to warm it beforehand, if even only for a short time.

I claim as my invention- 1. The method of sizing paper materials herein described, said method consisting in precipitating into aqueous fiber pulp, resin soap, or glue by means of solutions of tanning materials, substantially as and for the purpose set forth. p

2. As a new article, sized paper sized with animal glue or resin soap, in combination with tanning materials, and soluble in a large quantity of water, substantially as set forth.

In testimony whereof I have signed my name to this specification in the presence oftwo subscribing witnesses.

' ALEXANDER MITSCHERLICH.

Witnesses:

A. S. Hoetin, J. GRUND. 

